This research proposal has been designed to investigate the molecular nature of mamalian spermatogenic cell membranes. Particular emphasis will be placed on the isolation and biochemical characterization of cell surface antigens specific to mouse spermatogenesis. These experiments will utilize isolated populations of spermatogenic cells obtained from prepuberal and adult mouse testis. Cells to be used include: pre-type A spermatogonia, type A spermatogonia, type B spermatogonia, preleptotene spermatocytes, zygotene spermatocytes, pachytene spermatocytes, round spermatids, condensing spermatids, residual bodies and mature spermatozoa. The general objectives of this proposal include: 1) the isolation and characterization of cell surface constituents specific to pachytene primary spermatocytes and all subsequent spermatogenic cells, 2) the identification of cell surface constituents specific to spermatogonia and to primary spermatocytes prior to pachynema, 3) the determination of the temporal biosynthesis of particular membrane components throughout spermatogenesis, 4) the determination of the relative mobility of cell surface molecules throughout spermatogenesis and 5) the examination of the species specificity of isolated spermatogenic cell membrane constituents.